Fire-resistant hydraulic fluids



. 3,177,146 FIRE-RESISTANTHYDRAULIC FLUIDS CharlesE. Francis, Martinez,Calif., assignor to ,ShellOrl Company, New York, N.Y., a corporation ofDelaware N o Drawing. Filed Oct. 17, 1961, Ser. No. 145,754

' 'Claims. (Cl. 252--75) v United States Patent 07 their poor stabilityand their inability-to pass fire-resistant requirements for which suchfluids are primarily used.

In colliery equipment such as various hydraulic machinery, e.g., winderbrake mechanism and wagon tipper to hydraulic jacks, pit props and roofbar straighteners, mechanical loaders and various other fluid drivemechanisms which are subject to load, shock and vibration, it isessential that the hydraulic fluid employed therein function properlyand efliciently without the danger'of being flammable or toxic.

A variety of so-called fire-resistant fluids are commercially availablesuch as phosphate ester base fluids, but

these have been found to possess poor low temperatureviscosity-temperature properties, and they are toxic. Water-glycolsolution or various water-oil emulsions have been found to have atendency to form deposits and cause wear under high pressures and arecostly. Also most emulsifiable oil concentrates when emulsified withhard water tend to form deposits whichadversely affects the equipment. 7

It is an object of this invention to provide a composition which can beemulsified readily on the job to yield a fire resistant hydraulic fluidhaving good lubricating properties. Another object is: to provide afluid which after emulsificat'ion I is a satisfactory lubricant forcolliery hydraulic equipment, which is stable, non-toxic,fire-resistant, resistant to deterioration, inhibits corrosion and notcause wean Still another object of this invention is to providea'water-mineral oil emulsion usable as lubricants and fire resistanthydraulic fluids for various equipment used in colliery hydraulicequipment. Still another object of this invention is to provide an oilconcentrate which is readily emulsifiable with soft or hard water andcapable of forming water-in-oil emulsions which are stable over a widetemperature range.

These and other objects are accomplished in accordance with thisinvention by providing a water-in-oil emulsion which comprises fromabout to, about 45% of water phase and from about 55% to about80% of oilphase, the emulsion containing three essential additives namelyftw'oparticular types of dissimilar non-ionic surface active agents and awater-soluble polymeric derivative of an acrylic acid represented'by theformula:

ota-. 1 ra t 1 md where R is hydrogen or. a C 4 alkyl radical, R and R"may be hydrogen or lower alkyl radicals of up to 8 carbon atomsor theymay be. mixtures of hydrogen and a lower alkyl radical, M is a cationsuch asanalkali metal such as lithium, sodium or potassium, or ammoniaor an organic base, x is a positive integer, y may be zero 3,177,146 IPatented Apr fi, 1965 or a positive integer and z may be zero or apositive integer, the molecular weight of the polymer varying from atleast 1000, up to 500,000, preferably between 25,000 and'300,000.Instead of a polymer as represented by (I) a mixture of water-solublehomopolyrner's containing the desired groups :R CH3C O OM (II and I l- RL lg NRRL (III,

or polymers of (II) or (III) admixed with polyacrylic acid (IV).

The two non-ionic surface agents which are added to the mineral oil are(1) a monoester of a long chain fatty acid having at least 8 carbonatoms and an inner'ether of aliphatic polyhydric alcohols such ashexahydric alcohols and (2) a polyalkyleneoxy phenoxy alkanol. Each ofthese additives must be present in critical amounts of which themonoester (1) is used in amounts ranging from 1% to 4%, preferably from1.5% to 3% and the polyalkyleneoxy phenoxy alkanol (2) isused in amountsranging from 0.5% to 3%,preferably from 1% to 2%.

In the monoester non-ionic surface agent the inner ether alcohol isprepared by partially dehydrating polyhydric alcohols whichv results inthe conversion of the polyhydric alcohol to inner ether polyhydriccompounds having '1 or 2 ethers and 4 to 6 hydroxyl groups in themolecule in the manner described-in US. Patent 2,322,820. Compounds ofthis type, are exemplified by sorbitan, mannitan, xylitan, dulcitan,etc. Fatty acids which are used to form the monoesters of the innerether polyalcohols are saturated a-nd unsaturated fattyacidshavingatleast 8 carbon atoms, preferably from 12 to 18 carbon atoms, such I;aslauricgstearic,.oleic, linoleic, ricinoleic acids and the '.like..,Monoesters of this type include'sorbitan monolaurate, sorbitanmonostearate,.sorbitan monoole'ate, sor- .bitan monoricinoleate,mannitan monolaurate, mannitan monooleate, and mixtures thereof.Compounds of this type are available commercially as Span 20, 60 or fromthe Atlas Powder Company.

' The second essential additive is an oil-soluble alkyl phenoxypolyalkylene glycol having the formula propanol, and mixtures thereof.

The water-soluble copolymer or mixtures of homopolymer as defined by theabove formulas can be prepared by any suitable means well known to theart. .Thus the copolymers of Formula I can be prepared by copolymerizinga mixture of acrylic acid and acrylamide and reacting the copolymer withan alkali metal hydroxide to convert wholly or in part the acid groupsto alkali metal carboxylate groups or an acrylamide may be polymerizedand hydrolyzed inthe presence'ofapolymerization catalyst and alkalimetal hydroxide. The catalysts include inorganic or organic peroxides,or per-acids orazo catalysts .suchas V hydrogen peroxide,.. diethylperoxide, benzoyl peroxide,

sodium or. potassium persulfiate, azocatalyst, e.g., alpha!-alphaJ-azodiisobutyronitrite, etc. and the-alka'li metal hydroxide.includes sodium, potassium and lithium hydroxparts o-f water and (b)aqueous mixture of about 400 parts 900 parts water and reacting the two(a) and (b) at about 80 C. in the presence ofan inert atmosphere. Theproduct'contained a mixture of acrylamide and sodium .car-, boxyl groupsand had ,a viscosity-of 12,000-2l,000 cps.

Other water-soluble polymers in the'molecul-ar weight range of5000-400,000 include sodium polyacrylate, so-

.ides. Thus;asodium'polycarboxylate polyac rylamid'e (X) was' preparedby admixing solutions of (a). aqueous :solutions containing about 5500'parts of acrylamide and 4000.

of sodium hydroxide, 70 partsof potassium persulfate and diumpolymethacrylate, sodiumpolyacrylate-po1yacrylic acid, potassium.polyacrylate-polyacrylamide, potassium and homopolymer of acrylic acid(60/40), mixture ofpolymer (X) and polyacrylic acid (Y) and the like.

Although water-soluble polymers of the above typeare useful asthickeners, as polyelectrolytes, as fluocculants,

etc., their use in .hydraulicsystems with which the present invention isconcerned is new, novel and unexpected. The

polymers are dispersed in the waterphase of emulsions of watercontaining the polymer to] desired degree.

In addition to the above three essential additives it is preferred touse in such compositions small amounts of:

from about 0.01% to about 2%,preferably from about 0.2% to about 1%optional'additives which include antioxidants and antiwear agents.-The-antioxidants include phenolic, amine and/or metal thiophosphatecompounds.

The phenolic compounds are illustrated by the "alkyl phenols, e.g.,di-and trialkyl'phenols, for instance, 2',4-, 2,3-

3,4-, and 2,6- and 3,5-diamylphenol; 12,4-dimethyl-6-tert. vbutylphenol, 2,6-ditert.butyl 4-methylphenol. The amines are illustratedin ar ylamines such as phenyl-alpha-naphthylamine orphenyl-beta-naphthylamine. The metal thio phosphates are illustrated byalkaline earth metal thiophosphates, e.g., calcium or zincdimethylcycl'ohexyldithiophosphate. The. antiwear agents are sulfur-containingcompounds such as oil-soluble polychlo'ro hydrocarbyl thiocarbonateesters, e.g., polychloronaphtha methyl xanthate marketed by MonsantoChemical Co. under .the

name ,SantopoidS and characterized by sp. gr. 1.19 at. 60/60 'F.,fiashpoint 250 F., viscosity 63 cs. at, 100

F., sulfur 11%, chlorine 31%. Thi'ocarbonates ofithis type are preparedby reacting a chlorinated petroleum I naphtha with an alkali metal(potassium) amyl dithiocarg bonate; organic sulfides such asdibenzyldisulfide' or di- 'chlorodibenzyl disulfide. Dyes andantifoaming agent can Oil-soluble be added. to composition ofv thisinvention. dyes include naphthol yellow, Sandoz yellow, methylene blue,.aliz'arin compounds, etc.', 'while anti-foaming agents include siliconepolymer (DC-200 fluids ranging in vis cosity in centistokes from 100 to1000 at 250 C.) or-sili cone type A fluidmade by Dow-Corning Co. anddescribed in US. Patents 2,563,588and 2,662,055and mixtures thereof. 7

The oil may beentirely a hydrocarbon oil of wide -vis cosity range,e.g'.,from less than SOSUS atlOO F. to 15 0 SUS.at 210 F. Oils of thistype can :beobtain'ed from various crudessuch as parafiinic,naphthenicor mixed basecrudes; refined oi-ls in the lubricating oilviscosity range are preferred. On the other hand, the hydrocarbon ,ingor after it is prepared'is not necessary. If desired, the emulsioncanbeput through a homogenizer to insure 7 shipping costs can bereduced.

oil may be blended with fixed oils such as castor oil, lard oil andvthe'like and/or with synthetic lubricants suchas polymerized olefins,organic .estersyofi organic and inor- I ganic acids, e.g.,di-Z-ethylhexyl sebacate, dioctyl phthal-- ate, trioctylphosphate;polymeric tetrahydrofuran, polyalkyl silicone polymer,- e.g.,dimethylsilicone polymer and the like. Where'mixtures or blends are usedthe hydrocanbon oil such .as atmineral-lubricatingzoil is always presentin the predominant amount such as from 60% to about of the oil :blend.1' Astraightmineral lubricating oil, havingga viscosity index of atleast 50. and ranging inviscosity at 1009--F.

"of from '75 to 400 SUS, usually preferred. When it is derived from-alubricating .oil stock of lowviscosity index it is readily provided-asraflinate in a selectivelsolvent extraction process as is wellunderstood in thejart. The

emulsion can be preparedby adding. the required amount of watercontaining the polymeric compound as described to an oil,containingtheother two essential additives, while constantly stirring the mixture.Heating the; emplsion dura more, stable emulsion- Instead of making thefinished emulsion, the :oil concentrate, composition can be prepared and.thejre'quired. amount of water containing a polymeric compound asdescribed added whenthe emulsion lubricant is ready .foruse. In ,thisway storage and Illustrative examples of:minera1 oilbases of thisinvention which are emulsified ,iwith ,from about 20% 'to about 45%,preferably fromaboutt 30% to about 40% of water. containingpolymericacylo compound to form a stable fire-resistanthydraulic fluid. arepresented below.

Composition A1 Percent wt. Sorbitan-monooleate :2Diisobutylphenoxy(ethoxyhethanol 1 Mineral oil Balance Composition B:

Sorbitan monostearate 2 Diisobutylphenoxy(ethoxyhethanol 1 Mineral oilBalance Composition C:

Mannitan monooleate a. 3 Diisobutylphenoxy(ethoxy) ethanol 1 Mineral.oil Balance Composition -D: 7 i

Sorbitan monooleate f 2 Diisobutylphenoxy(ethoxy) ethanol 12,6-ditert.butyl-4-methylphenol 0.2 'Phenyl-alpha-naphthylamine f 0.1Mineral oil Balance Composition E1 V V Sorbitan monooleate I 2Diisobutylphenoxy(ethoxy) ethanol l 2,6-ditert.butyl-4-methylphenol 0.2Phenyl-alpha-naphthylamine r 0.1

Mineral oil' ,Balance Composition F: V

Sorbitanrnonooleate 2 Diisobuty1pl1enoxy,(ethoxy) ethanol 14,4'-methylene(2,6 ditert.butylphenol) 'Phenyl-alpha-naphthylamine. a0.1

Mineral. oil Balance Compo'sitionG:

Diisobutylphenoxy(ethoxy) ;ethanol 14,4,'-methylene(2,6-ditert.butylphenol) i 0.2 Phenylralpha-naphthylaminei 0.1 Mineral oil Balance pm a...

The finished emulsion fluid is prepared by slowly adding to the oil basecompositions such as A, B, C, D, E, F, G or H, from 20% to 45 based onthe total composition, an aqueous base, such as water which contains0.1% sodium polyacrylate-polyacrylamide (X) for compositions A, B and F,0.05% sodium polyacrylate-polyacrylamide (X) for composition D, 0.1%potassium polyacrylate-polyacrylamide (X) for composition C, 0.2%

' polyacrylic acid +01% sodium polyacrylate-polyamide' (X) forcomposition'E, 0.2% ammonium polyacrylatepolyacrylamidetX) forcomposition G and 0.1% lithium polyacrylate-polyamide (X) forcomposition H. The water base may or may not contain 0.014% of acorrosion or wear inhibitor such as water-soluble inorganic nitrites,nitrates, chromates, phosphates or water soluble low molecular weightsalts such as alkali metal or alkaline earth metal (Na, K, Ca, Ba)acetate or propionate. The water-in-oil emulsion can be mixed by anysuitable means such as by air agitation, propeller agitation or bypassing through a colloid mill until a homogeneous stable water-in-oilemulsion is formed. For economical reasons, the water is added to theoil in desired amounts at the 7 time the emulsion is to be used,although a stable waterin-oil emulsion can be prepared and stored for amoderate period. i

A'finished water-in-oil emulsion (Composition-l) wasprepared by admixing60% of composition D with 40% water and the mixture was passed through acolloid mill until a stable homogeneous water-in-oil emulsion wasformed.

Other finished compositions include:

Percent Ca petroleum sulfonate and/ or Ca C alkyl salicylate ignitedafter 5 cycles.

I claim as my invention: 1. A water-in-oil emulsion lubricant andhydraulic fluid which is from about 20% to about 45% water: phaseconsisting essentially of water and from about 0.01% to about 2% of awater-soluble polymeric compound having a molecular weight in the rangefrom 1,000 to 500,000

and having the formula R i FF IE i F i -o1-r,- Y

OM x OH y where R is a radical selected from the group consisting ofhydrogen and a C alkyl radical, R and R" are radicals selected from thegroup consisting of hydrogen and an .alkyl radical of up to 8 carbonatoms, M is a cation selected from the group consisting of an alkalimetal, ammonium, and an organic base, x is a positive integer and y and2 may be zero and positive integers, and from about 55% to about 80% oilphase, the oil phase being essentially a high viscosity index mineraloil having a viscosity in the range from 50 SUS at 100 F. to 150 SUS at210 F. containing (1) from about 1%, to about 4% of a monoester of along chainfatty acid having'at least 8 carbon atoms and an inner etherof an aliphatic polyhydric alcohol having 1-2 ether and 4-6 hydroxylgroups,

1 Water contains the corresponding water-soluble polymeric additivenoted above used to blend with Compositions A to H, respectively and inamounts indicated.

Samples of Compositions I and V were stored in 100 ml. cylinders at 1 t0F. and observed for phase separatron. The marked improvement instability afforded by the inclusion of the polymers, as in CompositionsI and V as compared to Composition W, is shown by Table I.

Table I Composition I V 1 Emulsion Stability Oil Water Oil Water OilWater at 140 F.

Separation, percent 1 day slight slight 1 slight 1 slight 1 1 5 1 15slight 3 1 9 1 37 slight 3 2 ll 1 45 30 days 7 2 '15 1 40 days 9 2 l8 1Composition W: [water-in-oil emulsion comprising 40% plus 60% mineraloil composition containing 2% sorbitan diisobutylphenoxy (ethoxy);ethanol 7 plus 0.2% 2,6-di-tertiary-4-methyl phenol plus 0.1% phenylalpha naphthylamine] monooleate plus 1% and (2) from about 0.5% to about3% of an oil-soluble alkyl 'phenoxy polyalkylene glycol havingtheformula R-phenyl(OR) OR"OI-l where R is an alkyl radical having 4m 20carbon atoms; and R and R" are alkylene' groups having 2 to 3 carbonatoms; and n is an integer of from 2 to 6.

2. A water-in-oil emulsion lubricant and hydraulic fluid which is fromabout 20% to about 45% water phase consisting essentially of water andfrom about 0.01% to about 2% of a water-soluble alkali metalpolyacrylate having a molecular weight in the range from 25,000 to300,000, and from about 55% to about oil phase, the oil phase beingessentially a 80-100 V.I. mineral oil having a viscosity in the rangefrom 75 to 400 SUS at F. containing (1) from about 1.5% to about 3% of amonoester of a fatty acid from 12 to 18 carbon atoms and an inner etherof an aliphatic hexahydric alcohol having 1-2 ether and 4-6 hydoxylgroup and (2) from about 1% to about 2% of an oil-soluble C alkylphenoxy(ethoxy) ethanol.

3. The composition of claim 2 containing in the emulsion from 0.01% to2% of an oil-soluble antioxidant selected from the group consisting ofalkyl phenols, phenyl-alpha-naphthylamine, and mixtures thereof, saidalkyl phenols having 2 to 3 alkyl groups having from 1 to 5 carbonatoms.

4. A water-in-oil emulsionlubricant and hydraulic fluid which is fromabout 20% to about 45 water phase consisting essentially of Water andfrom about 0.01% to about 2% of a water-soluble alkali metalpolyacrylatepolyacrylamide having a molecular weight in the range I from25,000 to 300,000, and from about 55% to about 80% oil phase, the oilphase being essentially a 80-100 V1. mineral oil having a viscosity inthe range from 75 to 400 SUS at 100 F. containing 1) from about 1.5% toabout 3% of a monoester of a fatty acid havingfrom 12 to 18 carbon atomsand an inner ether of an aliphatic he-X-ahydric alcohol having 1-2 etherand 4-6 hydroxyl groups and (2) from about 1% to about 2% of anoilsoluble C alkyl phenoxy(ethoxy) ethanol.

5. The composition of claim 4 containing in the emulsion from 0.01% to2% of an oil-soluble antioxidant selected from the group consisting ofalkyl phenols, phenyl-alpha-naphthylamine, and mixtures thereof, saidalkyl phenols having 2 to 3 alkyl groups having from 1 to 5 carbonatoms.

.(ethoxy Methanol.

-6.-A -water-in-oil emulsion lubricant and hydraulic fluid which isfromabout 120% to about 45% water phase consisting. essentially of waterand from about'0.0l% to about 2% of a water-soluble alkali metalpolyacrylatepolyacrylicvacid having a molecular weight in the range from25,000 to 300,000, andfrom about 55% to about 80% oil phase, the oilphase beingtessentially a 80- 100 V.I. mineral oilhaving a viscosity inthe range from 75 I to 400 SUS at 100% F. containing (1) from about 1.5%to about 3% of a monoester of a-fatty acid having from 12 to 18carbonatoms and an inner ether of an aliphatic hexahydric alcohol having1-2 ether and4-6 hydroxyl groups and (2)"from about 1% to about 2% of anoilsolubleCg alkyl phenoxy(ethoxy)Methanol.

7. A water-in-oil emulsion lubricant and hydraulic, b

fluid which is from about 20% to about water phase consistingessentially of :water and from, about 0. 02%*to' about 1% of awater-soluble sodium polyacrylate-polyaorylamide having a molecularweight in the range from 25,000 to 300,000, and from about to about 80%oil phase, ;the oil phase being essentially a 80-100. V.I.

mineral lubricating oil having a viscosity in the range from to 400 SUSat 100, F; containing from. about 1.5% to about 3 of a sorbitanmonooleate and from about 1% to about 2% of C alkyl substituted mixtureof phenoxy- 8. A water-in-oil emulsion lubricant and hydraulic fluidwhich is fromvabout 20% toabout 45% water phase consisting essentiallyof water and from about 0.02% to about 1% of' a water-soluble sodiumpolyacrylate-polyacrylic acid having a molecular weight in the range.from,25,000 to 300,000, and from about-55% to about oil phase, the oilphase being essentially a 80-100 V.-I.imineralllubricating oil having aviscosity in the, range from 75 to 400 SUS at Rcontaining from about1.5% to about 3% Ma sorbitan monooleate, and

I from about 1% to about;2% of a C alkyl substituted mixture of phenom(ethoXy)Methanol.

9. The composition of'claim 8 containing in the emulsion from about0.01% to about. 11% each. of 2,6- ditert.b-utyl-4-methylphenol,phenyl-alpha-naphthylamine and zinc diamyldithiocarbamate.

10. A water-inaoil emulsion lubricant and hydraulic fluid which isfromabout 30% to about;40% water phase consisting essentially of water andfroinabout 0.02% to about 1% of a water-soluble sodiumpolyacrylate-polyamide having a molecular weight in the; range from25,000 to, 300,000, and from'about 70% to about 60% oil phase, the oilphase being essentially a ,80100*V.-I.' mineral lubricatingoil having aviscosity in the range from 75 to 400SUS at 100, Fpcontainingfrorn about1.5% to 7 about 3% of sorbitanmonooleate, and from about.1% to about 2%,of anroil soluble diisobutylphenoxy(ethoxy) ALBERT T. MEYERS, PrimaryExaminer.

JOSEPH H. LIBERMAN, JULIUS GREENWALD,

' I Examiners.

1. A WATER-IN-OIL EMULSION LUBRICANT AND HYDRAULIC FLUID WHICH IS FROMABOUT 20% TO ABOUT 45% WATER PHASE CONSITING ESSENTIALLY OF WATER ANDFROM ABOUT 0.04% TO ABOUT 2% OF A WATER-SOLUBLE POLYMERIC COMPOUNDHAVING A MOLECULAR WEIGHT IN THE RANGE FROM 1,000 TO 500,000 AND HAVINGTHE FORMULA